It was a day after Nezuko had been accepted as Sakonji's student. She still couldn't believe that it is happening so fast. 

Tanjiro was still asleep, as Nezuko was finished to write a diary in her desk.

She looks at her brother sadly, but she knew it was for the best. 

Sakonji said, "Let's go, Nezuko." 

She closes her brother's door and followed his lead to begin her lesson of becoming a Demon Slayer.

Sakonji begins the lesson. "I know it's all brand new to you of becoming a Demon Slayer. To start things off, The Demon Slayer Crops has several hundred members. 

It is an organization that is unofficial to the government. Yet, in ancient times, it still exists and we continue to hunt demons today.

But as to who is leading the Demon Slayer Crops, that still remains a mystery." 

Nezuko listens in pure amazement, as she was hearing all of this for the first time.

"Demons! They're a stamp for food! They hunt down humans and eats them! No one knows where or when they came from.

Their physical abilities are incredible . Their wounds healed in a blink of an eye. 

Flesh is restored after being hacked off, and limbs can be newly regenerated . 

Some can shape-shift, some has otherworldly powers. 

They only be killed by the sunlight or be decanticated by a special sword.

Also, the Demon Slayers fight the demons with their own mortal bodies. Since they're human, their wounds will be slow to heal, as you are a human, and their limbs don't grow back!

Even so, they battle the demons, to protect the humanity. " 

Nezuko begins her training as her master explains of who he was. "I am a trainer. I literally train swordsmen. Since you're a girl, I would make it as an acceptance. 

As you should know, there are many trainers out there, and each of them train their own pupils in their respective homes. 

To join the Demon Slayer Crops, Nezuko, you have to face the Final Selection held at Mt. Fujisane.

Whether or not that you're eligible to go to the Final Selection is up to me." 

Nezuko said, "I know it's going to hard, but I'll do my best!" 

Nezuko thought in her mind, "Starting today, I'm keeping a diary for Tanjiro. I'm desending from the mountain today.

Don't worry about me, I'm going to keep training , and also going to pass the Final Selection! 

After repeatedly going down the mountain, I'm starting to learn how to avoid the traps. I think it's because I'm getting stronger. 

Also , I have adapted to the different scent around me, and can detect any scent than ever before since we left our house. 

Also, I hate to admit it, the traps , however , had been gone harder since then.

Mr. Sakonji was a tough sensei. I think he's trying to kill me." 

Nezuko has a sword in her hand, as she wrote an entry, 

"I made my desend with my sword in tow, Tanjiro, well, it did make an improvement on my balance, but..." 

Nezuko was held by one of the traps, as she thought back, "I still haven't managed to avoid the traps." 

"I also swing my sword too. Ok, to be totally honest, I swing my sword everyday. I kept going at it until my arms grew tired . " 

Sakonji explains to Nezuko, "Swords due to break so easily." 

Nezuko nods, as she thought, "Mr. Sakonji told me that even though its strong vertically, but in horzinally, it's a different situation, it's weak. 

You need to apply force straight along with the blade. 

The blade had to be in same direction in which you apply the force into, and he also added, " If you damage the sword, or in this case, break the sword, I'll break your bones as well." 

I haven't been more scared of my sensei when he mentions that little possibility. " 

Nezuko was about to drift off , but she rubs her eyes, "Tanjiro, I'm not giving up." 

Nezuko was in still in training for the Final Selection . She wrote again another entry for her brother. 

"Tanjiro, today.. was a little bit more training. Today, I have to learn how to stand up . Training to break my fall and get up quickly as I possibly can in any situation. 

I tried my best to get Sensei Sakonji, as I possibly can, through. I wished you could've seen the outcome." 

Nezuko sweats as she imagines if Tanjiro sees his little sister charging at her sensei like crazy. 

"However, Sensei was bare handed and unarmed. And incredibly powerful as he flips me up like it was nothing!" 

Nezuko looks at her brother from training, "I'm home again." 

She wrote another entry , "Today, I learn other breathing methods. " 

Nezuko's eyes blink in total interest as she ask, "Total Concentration Breathing?"

"That's right, Nezuko, and today, I'm going to show you how to master the new moves you need to be in the Final Selection." Her sensei nods.

"Also there are ten forms in total." 

"Ten forms?!?" Nezuko gasps in shock of learning that Total Concentration Breathing has so many forms.

"Remember to take a deep breath, so the oxygen flows in every cell of your body. In this way, your body would enhance your healing power, both to stabilize and energize your spirit." Sakonji explains.

"Relax your upper body, while you bracing your lower half." 

Nezuko was amazed of it, as this was something she never thought before. "Sensei is truly amazing. " 

He also told Nezuko to be one with the water . Nezuko look down at the waterfall, "Are you sure you want me to go down there, Sensei?"

Just like that, he pushed her down without giving her a second thought. 

It also marks that Tanjiro wasn't able to wake up for six months. It was hard for Nezuko , as she was worried about Tanjiro wouldn't be able to wake up from his slumber. 

Nezuko makes sure of her older brother's well -being, as she thought in her mind, "Tanjiro, I really miss you. I hope that you wake up soon." 

Nezuko begins her training once again, as she wrote, "The training is much harder than ever. The air was getting thinner than I usually train in. 

And each time I train, I thought about was you, Tanjiro. You're the movation I held on to, to never give up . "

Then all of a sudden , in one year since Nezuko and Tanjiro's arrival at the mountain, he said one thing to her.

"I have nothing to teach you now, Nezuko. The rest is up to you now.

Wither or not you would go up the next level. Come with me." 

Nezuko follows her master's lead, curious of what lies in store for her. 

As they stopped, Nezuko gasps as she saw a giant boulder and it has been attach to a rope around it.

Her master said, "If you can slice this boulder, I will allow you to enter to the Final Selection." 

She looks at her sensei with an amazed expression that he had challenged her with something she never done before, as she looks at the boulder before her. 

She thought, "Can I possibly cut this boulder? If I do, I can be allowed to go to the Final Selection to become a full-fledged Demon Slayer. It wouldn't be an easy attempt, but I know I have to do this for Tanjiro's sake." 

Nezuko saw her master had disappeared from her, as she knew that is the final test . She took everything she had learnt from her sensei, to never give in.

"Come on! I can't give up , Tanjiro is counting me !" She yelled, as the boulder wouldn't budge. But then to her sudden amazement , a voice that she was unfamiliar with, said, "Shut up! You're not going to be able to slice anything if you complain too much." 

She looks up to see a person wearing a fox mask. 

"A person with a fox mask? Where did he come from?" Nezuko thought in surprised look, of having a person other than herself appeared before her.

He attacks her as Nezuko tries to bear the pain, "You're really pathetic . You called yourself a swordswoman?"

Nezuko stands up, "Wait just a moment! Why you attacking me for? Who are you?"

The boy replied, "Just answer me this. You think what you're doing is worth it? You'll never going to slice that boulder like I did! I'm more powerful than you!" 

Nezuko was stunned. "He can cut the boulder?!? Then I must defeat him! " She thought in her mind.

"Don't forget all your lessons that your Sensei Sakonji had taught you! Total Contraction Breathing!" 

Nezuko thought, "He know Sensei? And the Total Contraction Breathing Technique?"

"I never forgotten it! I practice everyday with each time I tried to, it seems harder than I thought it could be! " 

"You can do it, if you try further!  " The boy replied.

He knocked Nezuko down as he turns to his friend, a girl with a cat mask, "It's your turn now. I'll leave this part to you." 

The girl waited for Nezuko to wake up. "Are you all right?"

The girl woken up to her voice, as she was amazed at her of her sudden appearance. 

She said, "That was so amazing! I never fought anyone so strong before! I want to be stronger than he was. Do you think I can do that?"

The girl replied, "Of course you can, since I'm going to help you with your training." 

Nezuko learnt that the girl with the cat mask was named Makomo. She also told Nezuko the boy she had fought earlier was named Sabito. 

Makomo helped Nezuko by telling her what her defaults were , to be worked on, as she was amazed by her generous help. 

She helped Nezuko of her bad habits she saw and unnecessary moves with her sword. 

Nezuko did ask Makomo where she had come from, but she wasn't lucky to have a direct answer. 

She learnt that Sabito and Makomo isn't really siblings. They were raised as orphans and it turns out that Sakonji took care of them as if they were his own.

Makomo said to Nezuko , "You see, Total Concentration Breathing accelerates your body circulation and your heart rate. 

It causes your body temperature to spike, making you strong as a demon while you're still human.

Nezuko, the most important thing to remember is to expand your lung capacity. 

When you bring lots of air into your blood, and when your body gets excited , your bones and mulcules scurry to heat up and grow stronger. " 

Nezuko seems to understand it a bit, "Well, how do I do that?"

Makomo smiles, "Just train harder, Nezuko." 

Nezuko thought, "I trained as much as I could, but I still couldn't beat Sabito." 

It was six months later as Nezuko tries to compete the training with Makomo and Sabito.

When Nezuko finally challenges Sabito, he seems interested and intrigue with her as he finally held a real sword with him . 

"You're becoming a true Swordswoman after six months. Let's see how much you improved since we first met, Nezuko. Show me." Sabito said. 

"Sabito, Today, I'm going to beat you in this match! I wouldn't lose to you!" Nezuko yelled at the boy.

They both emerge at the same time, but finally , Nezuko's blade strikes first before Sabito gets a strike against her. The battle was over in an instant.

The fox mask was sliced in half, revealing Sabito's face for the first time. Nezuko glaces at the boy, as Sabito gave her a small smile over her win.

He was sad and happy at the same time. 

Nezuko was staring at him as Makomo said, "Nezuko, well done. You did great. Don't forget what you accomplish here." 

Nezuko looked at Sabito before he leaves, "Thank you , Sabito , for everything." 

He nods at the girl, as to her amazing discovery that she was able to slice the massive boulder without recognizing it.

"I guess this is it. That means I'm going to enter the Final Selection to become a Demon Slayer. 

Just watch me, Tanjiro." Nezuko said.